Keith Olbermann, NBC Part Ways Ahead of Comcast Merger (UPDATED)

(UPDATES to make clear the exact circumstances of Olbermann’s departure from NBC are unclear)

Former sports-announcer turned liberal cable talk-show host Keith Olbermann announced he was leaving his MSNBC prime time talk show Friday night.

It was not immediately clear what circumstances led to Olbermann’s leaving the network. TMZ is reporting that Olbermann was fired. But none of the principles have disclosed the circumstances of his departure, which Olbermann himself revealed in a surprise announcement at the end of what would be the last installment “Countdown with Keith Olbermann.”

The news came just days after Comcast’s purchase of NBC Universal received FCC approval — creating a $30 billion media conglomerate — and just days before Comcast takes control, raising obvious questions about the timing of the move. Comcast told wired.com it had nothing to do with the Olbermann decision — which stands to reason, since it is bound by federal law and FCC rules from influencing the company it will own until the purchase has legally closed.

NBC did not acknowledge a request for comment.

Olbermann had been an outspoken critic of the merger and in general a liberal lightning rod, getting into daily spats with Fox News (which he often called “Fox Noise”) and conservative radio talk show host Rush Limbaugh. He had two years left his contract, estimated at $30 million.

While transparently ideological, Olbermann portrayed himself as a modern-day heir to earlier broadcast giants, starting with Edward R. Murrow, the late CBS newsman who helped invent television journalism.